Controlling the flow of coolant to resistance welding electrodes

ABSTRACT

A first electrode coolant path is configured to cool a first welding electrode by liquid coolant flowing from a supply path through the first electrode coolant path to a return path. A second electrode coolant path is configured to cool a second welding electrode by liquid coolant flowing from the supply path through the second electrode coolant path to the return path. Three or more valves are configured to stop or reduce liquid coolant flow through the first or second electrode coolant path and configured to stop or reduce liquid coolant backflow from the return path when the first or second welding electrode is at least partially detached. At least one valve is coupled in the first or second electrode coolant path. A drawback apparatus generates a suction force to draw liquid coolant away from a gap formed when the first or second welding electrode is at least partially detached.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/849,247, filed Sep. 9, 2015 and entitled “Systems andMethods for Coolant Drawback,” and is a continuation of U.S. patentapplication Ser. No. 14/849,307, filed Sep. 9, 2015 and entitled“Drawback Valve Systems and Methods for Coolant Drawback,” now U.S. Pat.No. 10,022,815, both of which claim priority to U.S. Provisional PatentApplication Ser. No. 62/048,168, filed Sep. 9, 2014 and entitled “WaterDrawback,” all of which are hereby incorporated by reference herein.

BACKGROUND 1. Technical Field

The present invention(s) relate generally to liquid cooling systems.More particularly, the invention(s) relate to systems and methods forcooling welding electrodes and reducing coolant loss.

2. Description of Related Art

Resistance welding (e.g., spot welding) machines require cooling systemsto operate effectively. Typically, water cooling systems are used tocool the machine, or, more specifically, the welding electrodes.However, the welding electrodes are designed to be removed from thewelding machine (e.g., during a failure or for a scheduled maintenance)which can cause substantial liquid spillage. Such spillage may beharmful to the welding equipment, hazardous to operations personnel,and/or potentially dangerous in an environment of high electricalcurrent.

Although current systems may reduce spillage to some degree by simplyshutting off liquid flow at the source when a welding electrode is lostor removed, this is not optimal because spillage can still occur fromliquid already circulating in the cooling system.

SUMMARY

Some embodiments described herein reduce or eliminate liquid loss (e.g.,spillage) in liquid cooling systems which may operate in high electricalcurrent environments. Various embodiments described herein discussdrawback of liquid coolant from fluid paths of the liquid cooling systemFor example, in some embodiments, the system may drawback liquid coolantfrom the fluid paths in preparation for a scheduled system maintenanceor repair, and/or it may draw back liquid coolant in response to afailure of one or more system components (e.g., welding electrodes).

In some embodiments, a liquid cooling system for cooling weldingelectrodes is discussed herein. The system may include a first electrodepath configured to cool a first welding electrode by liquid coolantcirculating through the first electrode path. A second welding electrodemay be included for cooperating with the first welding electrode. Afirst valve element may be configured to stop or reduce flow of liquidcoolant through the first electrode path when the first weldingelectrode at least partially detaches. A first drawback element coupledto the first electrode path may be configured to drawback liquid coolantaway from a gap in the first electrode path that is formed when thefirst welding electrode at least partially detaches. The first drawbackelement may include at least a piston and a chamber, the pistonconfigured to drawback the liquid coolant away from the gap and into thechamber.

A second electrode path may include the second welding electrode and beconfigured to cool the second welding electrode by liquid coolantcirculating through the second electrode path. A second valve may beconfigured to stop or reduce flow of the liquid coolant circulatingthrough the second electrode path when the second welding electrode atleast partially detaches. A second drawback element may be coupled tothe second electrode path and configured to drawback the liquid coolantaway from a gap in the second electrode path that is formed when thesecond welding electrode at least partially detaches.

The liquid coolant circulating through the first electrode path may besupplied from a same coolant source as the liquid coolant circulatingthrough the second electrode path. Likewise, the coolant from both thefirst and second electrode paths may be returned to a shared coolantreturn. In other embodiments, the liquid coolant circulating through thefirst electrode path may be supplied from a different coolant sourcethan the liquid coolant circulating through the second electrode path,and likewise may be returned to a different coolant return.

In some embodiments, a third valve may be configured to stop or reducebackflow of the liquid coolant from the coolant return circulatingthrough the first electrode path when the first welding electrode atleast partially detaches. A third drawback element may be coupled to thefirst electrode path and configured to drawback the liquid coolant awayfrom the gap in the first electrode path. The third drawback element maybe configured to drawback the liquid coolant in a different directionaway from the gap in the first electrode path than the first drawbackelement.

In various embodiments, a fourth valve may be configured to stop orreduce flow of the liquid coolant from the coolant return circulatingthrough the second electrode path when the second welding electrode atleast partially detaches. A fourth drawback element may be coupled tothe second electrode path and configured to drawback the liquid coolantaway from the gap in the second electrode path. The fourth drawbackelement may be configured to drawback the liquid coolant in a differentdirection away from the gap in the second electrode path than the seconddrawback element.

The third drawback element may be disposed at an opposite side of thegap in the first electrode path relative to the first drawback element.The fourth drawback element may be disposed at an opposite side of thegap in the second electrode path relative to the second drawbackelement.

An exemplary method may be provided for cooling welding electrodes. Themethod may include cooling a first welding electrode by circulatingliquid coolant through a first electrode path in fluid coupling with thefirst welding electrode. The flow of liquid coolant through the firstliquid path may be reduced or stopped when the first electrode at leastpartially detaches, and the liquid coolant may be drawn back from a gapin the first electrode path that is formed when the first weldingelectrode at least partially detaches.

Some embodiments describe cooling a second welding electrode bycirculating liquid coolant through a second electrode path in fluidcoupling with the second welding electrode, stopping or reducing flow ofthe liquid coolant through the second liquid path when the secondelectrode at least partially detaches, and drawing back the liquidcoolant from a gap in the second electrode path that is formed when thesecond welding electrode at least partially detaches.

The method may include supplying the liquid coolant circulating in thefirst electrode path from a same source as the liquid coolantcirculating in the second electrode path, and likewise returning coolantfrom both paths to a common coolant return. In various embodiments, themethod may include supplying the liquid coolant circulating in the firstelectrode path with a different source as the liquid coolant circulatingin the second electrode path, and likewise returning coolant todifferent coolant returns. The method may include drawing back theliquid coolant in a different direction away from the gap in the firstelectrode path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a fluid flow system for cooling one or morecomponents of a welding machine according to some embodiments.

FIG. 2A is a diagram of a fluid flow system for cooling weldingelectrodes according to some embodiments.

FIG. 2B is a diagram illustrating fluid shutoff valves for the fluidflow system according to some embodiments.

FIG. 2C is a diagram illustrating detachment of a welding electrode inconjunction with the fluid shutoff of the fluid flow system according tosome embodiments.

FIG. 3A is a diagram of a fluid flow system for cooling weldingelectrodes including a fluid drawback apparatus according to someembodiments.

FIG. 3B is a diagram of the fluid drawback apparatus evacuating (or“drawing back”) fluid according to some embodiments.

FIG. 3C is a diagram of the fluid flow system including the fluiddrawback apparatus and additional shutoff valve(s) positioned along thefluid passageway(s) according to some embodiments.

FIG. 4 is a flowchart illustrating an example operation of a fluiddrawback apparatus (e.g., as shown is FIGS. 3A and 3B) according to someembodiments.

FIG. 5A is a diagram of a fluid flow system for cooling weldingelectrodes including independent fluid shutoff for multiple fluid pathsegments according to some embodiments.

FIG. 5B is a diagram illustrating a drawback apparatus providingindependent fluid removal for the path segments according to someembodiments.

FIG. 5C is a diagram illustrating a drawback fluid flow when a weldingelectrode is detached from the fluid flow system according to someembodiments.

FIG. 5D is a diagram illustrating a drawback fluid flow when bothwelding electrodes are detached from the fluid flow system according tosome embodiments.

FIG. 6 is a flowchart illustrating an operation of a fluid drawbackapparatus (e.g., as shown is FIGS. 5A-D) according to some embodiments.

FIG. 7A is a diagram of a fluid flow system for cooling weldingelectrodes including a drawback valve apparatus according to someembodiments.

FIG. 7B is a diagram illustrating a drawback valve apparatus operated bya single actuator according to some embodiments.

FIG. 7C is a diagram illustrating a drawback valve apparatus operated bymultiple actuators according to some embodiments.

FIG. 8A is a diagram of a drawback valve in a first position (e.g., an“open” position) according to some embodiments.

FIG. 8B is a diagram of a drawback valve in a second position (e.g., a“closed” position) according to some embodiments.

FIG. 8C is a diagram of a drawback valve in a third position (e.g., a“drawback” position) according to some embodiments.

FIG. 8D is a diagram of a drawback valve according to some embodiments.

FIG. 9 is a flowchart illustrating an operation of a drawback valve(e.g., as shown in FIGS. 8A-C) according to some embodiments.

FIG. 10A is a diagram of a drawback valve in a first position (e.g., an“open” position) according to some embodiments.

FIG. 10B is a diagram of a drawback valve in a second position (e.g., a“closed” or “drawback” position) according to some embodiments.

FIG. 11 is a diagram of a fluid flow system for cooling weldingelectrodes including independent fluid shutoff and drawback forpreventing or reducing liquid loss according to some embodiments.

FIG. 12 is a flowchart illustrating an operation of a liquid coolingsystem (e.g., system 1100) according to some embodiments.

FIG. 13 is a diagram of a fluid flow system for cooling weldingelectrodes including independent fluid shutoff and drawback forindividual fluid path segments of a single fluid path 1312 according tosome embodiments.

FIG. 14A is a diagram of a fluid flow system for cooling weldingelectrodes including a drawback valve apparatus and a return flow sensoraccording to some embodiments.

FIG. 14B is a diagram of a fluid flow system for cooling the weldingelectrodes including a drawback valve apparatus, a supply flow sensorand a return flow sensor according to some embodiments.

FIG. 14C is a diagram of a fluid flow system for cooling the weldingelectrodes 1402, 1404 including a drawback valve apparatus, supply andreturn flow sensors, and additional auxiliary equipment (e.g., atransformer) according to some embodiments.

FIG. 15 is a flowchart illustrating an example operation of a liquidcooling system (e.g., as shown in FIGS. 14A-C) configured to detect andrespond to malfunctions (e.g., at least one partially detachedelectrode, clogged paths, and so forth) according to some embodiments.

FIGS. 16A-B are diagrams of a fluid flow system for cooling weldingelectrodes including a drawback valve apparatus and flow sensorsaccording to some embodiments.

FIG. 17 is a diagram of a fluid flow system for cooling weldingelectrodes including a drawback valve apparatus, flow sensors, andtemperature sensors according to some embodiments.

FIG. 18 is a flowchart illustrating an example operation of a liquidcooling system (e.g., as shown in FIG. 17) including flow sensors andtemperature sensors according to some embodiments.

DETAILED DESCRIPTION

FIG. 1 is a diagram of a fluid flow system 100 for cooling one or morecomponents of a welding machine according to some embodiments. Thesystem 100 is illustrated as being a resistance welding system, althoughembodiments described herein are not limited to any particular system orapplication. At least some of the embodiments described herein may beadvantageously utilized in any fluid flow system in which it is desiredto liquid cool component(s) and/or drawback fluid from one or more flowpaths (or “passageways”).

The system 100 includes a resistance welding machine 102 having a hollowframe 104 which supports two vertically opposed welding electrodes 106and 108 made of copper or other suitable material. The electrodes 106and 108 may also be known as welding tips or caps. In operation, a workpiece 110, typically consisting of two or more metal sheets, can beclamped between the electrodes 106 and 108 and an electrical voltage canbe applied across the electrodes 106 and 108. This can cause a largeelectric current to flow from one of the electrodes 106 or 108 to theother through the work piece 110, raising a temperature of the workpiece 110 to a level which can result in localized melting and fusion ofthe individual sheets of the work piece 110 together.

Additionally, the high electric current passing through the electrodes106 and 108 may cause them to melt if cooling means are not provided.For this reason, cooling fluid flow paths (e.g., paths 212, 214discussed below) can be provided which can extend from an inlet leadingto a source of pressurized cooling fluid (e.g., water or other suitablefluid) through the apparatus 114 to fluid flow passageways in the frame104. Fluid can flow from the apparatus 114 through an inlet Y-connector116 to upper and lower fluid inlets 118 and 120 of the frame 104. Fluidcan exit the frame 104 through upper and lower outlets 122 and 124 andan outlet Y-connector 126 and flows through the apparatus 114 to a fluidoutlet and reservoir. In some embodiments, the apparatus 114 for themeasurement and control of cooling fluid can be of the type commerciallyavailable from Proteus Industries, Inc. of Mountain View, Calif. underthe trade name WELDSAVER™.

It will be noted that the arrangement of FIG. 1, as well as thefollowing figures, are by way of examples and not meant to limit thescope of embodiments described herein. Other typical configurationsinclude, for example, a series connection of upper and lower flow paths,in which case there are no Y-connectors. In addition, other devices suchas transformers, power supplies and high current cables which need to becooled may be inserted into the system 100.

FIG. 2A is a diagram of a fluid flow system 200 for cooling weldingelectrodes 202, 204 according to some embodiments. Such a system 200 canbe used, for example, to cool electrodes of a resistance weldingapparatus (e.g., welding machine 102). In the illustrated embodiment,more specifically, liquid coolant 206 (e.g., water) can flow from asupply source 208 (e.g., one or more pumps, reservoirs, etc.) throughwelding electrodes 202, 204, e.g., of the type described above, via oneor more fluid passageways. In the illustrated embodiment, thepassageways form a loop which can be logically divided into fluid paths212, 214. The liquid coolant 206 can be returned to the coolant source208 or otherwise discharged via coolant return 210.

As shown, liquid coolant 206 can flow through paths 212, 214, asindicated by arrows 216, thereby cooling the electrodes 202, 204, e.g.,to a temperature at which the electrodes 202, 204 will not melt or theirfunction be otherwise damaged by heat. Although two electrodes 202, 204and two corresponding fluid paths 212, 214 are shown here, otherembodiments may have a greater or lesser number of such electrodesand/or fluid paths. In some embodiments, the paths 212, 214 may compriseflexible and/or rigid tubing.

The illustrated electrodes 202, 204 may be detachably connected, e.g.,to the frame 104, by a press fitting or the like. One or both electrodesmay detach from the welding machine. An electrode can detach for avariety of reasons, such as scheduled maintenance, damage to theelectrode, or fusion of one or more of the electrodes to the work inprogress. The latter may be especially prevalent when welding galvanizedparts.

If either electrode 202, 204 detaches, a large quantity of fluid 206 mayspurt out of the fluid paths 212, 214 (unless one or more embodiments asdescribed herein are implemented). For example, if either electrode 202,204 detaches, fluid 206 may spray out of the resulting gap due to supplypressure, back pressure and/or gravity in the paths 212, 214. Spillageof fluid 206, especially in an environment of high electrical current,as mentioned above, may be unsafe, wasteful, and may impact the workenvironment or damage equipment. Various embodiments described hereinmay reduce or eliminate fluid leakage.

FIG. 2B is a diagram illustrating fluid shutoff valves 220, 222 for thefluid flow system 200 according to some embodiments. In someembodiments, flow of coolant 206 may be reduced or stopped, either inanticipation of electrode 202, 204 detachment, e.g., for maintenance, orin response to an unintentional detachment of an electrode 202, 204,e.g., during a failure. More specifically, shutoff valve 220 can be usedto reduce or stop coolant flow from the supply 208, and shutoff valve222 can be used to prevent backflow from the return 210. For example,valve 220 can be a solenoid or pneumatically actuated valve, and thevalve 222 can be a non-return check valve, although in other embodimentsit may be otherwise.

FIG. 2C is a diagram illustrating detachment of the welding electrode202 in conjunction with the fluid shutoff of the fluid flow system 200according to some embodiments. Detachment of electrode 202 inconjunction with shutoff of the coolant supply 208 and return 210 cancreate a severed loop, open at two ends 230, 232, and filled withcoolant 206. With both ends 230, 232 open to atmosphere, a gap 236 isformed and coolant 206 may readily escape.

In some embodiments, upon detachment of a welding electrode, e.g.,welding electrode 202, the shut off valves 220 and/or 222 may beactuated thereby shutting off flow of fluid through fluid pathways 212and 214. By shutting off the flow of fluid, fluid loss caused by thedetached welding electrode 202 may be reduced.

It will be appreciated that the shut off values 220 and/or 222 maydetect detachment or be commanded to actuate in any number of ways. Forexample, the shut off valves 220 and/or 222 may shut off fluid flow upondetection of a change in pressure or other fluid flow conditions. Inanother example, the shut off valves 220 and/or 222 may be incommunication with a sensor that detects if the welding electrode 202becomes detached, e.g., through electrical communication with thewelding electrode 202. The sensor may send commands to one or both shutoff valves 220 and 222 to shut off flow of fluid. In a further example,the shut off valves 220 and 222 may be commanded to shut off the flow offluid by a robotic automation system or worker at the fluid flow system200, e.g., electronically in a manner similar to the sensor ormechanically. In yet another example, the shut off valves 220 and/or 222may shut off if the flow of fluid stops in either fluid pathway 212 or214.

FIG. 3A is a diagram of a fluid flow system 300 for cooling weldingelectrodes 302, 304 including a fluid drawback apparatus 340 accordingto some embodiments. As shown, the system 300 includes weldingelectrodes 302 and 304, coolant supply 308, fluid passageway 312, 314,coolant return 310, shutoff valves 320, 322 and drawback apparatus 340.It will be appreciated that the features of system 300 may be the sameor different from the corresponding features discussed herein (e.g.,welding electrodes 202, 204, shutoff valves 220, 222, welding electrodes502, 504, and the like).

The illustrated drawback apparatus 340 includes a drawback chamber(e.g., a cylinder) 342 and a drawback piston 346 disposed therein.Movement of the piston 346 can create a suction force that may drawcoolant 306 from the passageway 312, 314 into the cylinder 342 when, forexample, either electrode 302 or 304 is at least partially detached.Further description of the drawback apparatus 340 in variousconfigurations can be found below. It will be appreciated that thedrawback apparatus 340 may be coupled to the supply line 350 asillustrated, or to the return line 352.

In one example, the drawback apparatus 340 may draw coolant 306 frompassageway 312 and/or 314 if electrode 302 and/or electrode 304 aredetached. The drawback of the coolant 306 by the drawback apparatus 340may draw the fluid 306 away from any breaks or gaps in the passageway312 and/or 314. In some embodiments, the drawback apparatus 340 may drawfluid, e.g., coolant 306, at the same time or approximately when theshutoff valves 320 and/or 322 shut off fluid flow. For example, thedrawback apparatus 340 may create a suction for drawing back coolant 306immediately preceding the removal of either electrode 302, 304 forroutine or scheduled maintenance.

FIG. 3B is a diagram of the fluid drawback apparatus 340 evacuating (or“drawing back”) coolant 306 according to some embodiments. The drawbackapparatus 340 can be employed to drawback coolant 306 from the fluidpassageway 312 to prevent or reduce coolant 306 escape from a gap 336that is formed when the welding electrode 302 detaches (see FIG. 3A).The gap 336 can be an air gap, or other vent to atmosphere. Although theelectrode 302 is shown fully detached, it will be appreciated that thedrawback apparatus 340 can be employed when any gap is formed, e.g.,when the electrode 302 partially detaches or when the pathways 312and/or 314 are broken.

As shown, the drawback apparatus 340 is placed on fluid supply line (or“path” or “segment”) 350 in order to intersect the passageway at a pointwhich divides the passageway 312 into a short segment 312 b on one sideof the gap 336 and the passageway 314 plus a part of the passageway 312into a long segment 314 b on the opposite side of the gap 336. It willbe appreciated that “segments” can also be referred to as “paths.”

In other embodiments, the drawback apparatus 340 can be placed on fluidreturn line (or “path” or “segment”) 352 in addition to, or instead of,on the supply line 350. In the illustrated embodiment, the drawbackapparatus 340 can have a liquid volume capacity sufficient to evacuateall of the coolant 206 from the passageways(s) 312, 314. For example,the volume capacity can be 250 cc. Drawing back the coolant 306 by thecoolant drawback apparatus 340 draws coolant 306 away from the gap 336thereby preventing or reducing coolant 306 loss. In some embodiments,evacuating the short segment 312 b can create a vent to atmosphere onthe long segment 314 b, thereby preventing or reducing any furthercoolant 306 removal. In various embodiments, the coolant drawbackapparatus 340 draws coolant 306 back after the shut off valves 320 and322 362 have shut off flow of coolant 306.

In some embodiments, as illustrated in FIG. 3C, the system 300 mayinclude one or more additional shutoff valves 360 and/or 362 (e.g.,non-return check valves) positioned along the fluid passageways 312,314. For example, valve 360 may be positioned at an outlet of passageway312 and valve 362 may be positioned at an outlet of passageway 314.Depending upon their placement and number, valves 360 and/or 362 mayeliminate the necessity of valves 320 and/or 322, e.g., as shown byomission of valve 322. The valves 360, 362, may be shut offautomatically (e.g., by an actuator, computer, or the like) or manually(e.g., by an operator) at the same or approximately same time as thevalves 320, 322. Such a configuration may, for example, reduce and/orprevent liquid spillage from passageways 312, 314 when the electrodes302, 304 are at least partially detached, by blocking the possible ventto atmosphere on the long segment 314 b. This may leave a segment 312 cwithout coolant drawback from the gap 336 when electrode 302 is detachedas shown, but, in some embodiments, the typically small geometries ofthe passageways adjacent to the electrodes may allow for surface tensionof the coolant to prevent substantial spillage. It will appreciated thatalthough two additional valves 360, 362 are shown here, in otherembodiments, a greater or lesser number of such valves may be used,and/or positioned elsewhere on passageways 312, 314.

FIG. 4 is a flowchart illustrating an example operation of a fluiddrawback apparatus (e.g., drawback apparatus 340 as shown in FIGS. 3Aand 3B) according to some embodiments. It will be appreciated thatalthough the steps 402-408 below are described in a specific order, thesteps 402-408 may also be performed in a different order. Each of thesteps 402-408 may also be performed sequentially, or serially, and/or inparallel with one or more of the other steps 402-408. For example, step402 can be performed simultaneously or nearly simultaneously (i.e., inparallel or nearly in parallel) with step 404. In some embodiments,operation of the drawback apparatus may include a greater or lessernumber of such steps.

In step 402, a first welding electrode (e.g., welding electrode 302) iscooled by circulating liquid coolant (e.g., coolant 306) through a firstliquid coolant path (e.g., path 312) in fluid coupling with the firstwelding electrode. More specifically, a coolant supply (e.g., supply308) may supply liquid coolant to the first liquid coolant path via asupply line (e.g., supply line 350). Since the first welding electrodeis included in the first coolant path, the first electrode is cooled bythe circulating liquid.

In step 404, a second welding electrode (e.g., welding electrode 304) iscooled by circulating liquid coolant (e.g., liquid coolant 306) througha second liquid coolant path (e.g., path 314) in fluid coupling with thesecond welding electrode. More specifically, a coolant supply (e.g.,supply 308) can supply liquid coolant to the second liquid coolant pathvia a supply line (e.g., supply line 350). Since the second weldingelectrode is included in the second coolant path, the second electrodeis cooled by the circulating liquid.

Although in the illustrated embodiment the first and second paths aresupplied coolant by the same source (e.g., supply 308), in otherembodiments they may be supplied by different sources (e.g., supply 308and a separate supply source). For example, each path may be separatefrom each other and/or each path may include one or more separatecoolant supplies.

In step 406, flow of liquid coolant through the first liquid coolantpath is stopped or reduced when the first electrode at least partiallydetaches. A shutoff valve (e.g., valve 320) positioned on the supplyline can be manually (e.g., by a human operator) or automaticallytriggered (e.g., by an actuator, computer, or the like), either inanticipation of, or response to the electrode at least partiallydetaching. As discussed above, the electrode can detach for a variety ofreasons including, but not limited to, a scheduled maintenance or afailure, e.g., melting and/or fusion of the electrode to the work inprogress (e.g., work piece 110).

In step 408, the liquid coolant is drawn back from a gap (e.g., gap 336)in the first liquid coolant path that is formed when the first weldingelectrode at least partially detaches. For example, a drawback apparatus(e.g., drawback apparatus 340) can create a suction (e.g., via movementof piston 346) that draws the coolant away from the gap and into achamber (e.g., chamber 342). The coolant may be drawn back from the gapon either or both sides of the path to the gap.

FIG. 5A is a diagram of a fluid flow system 500 for cooling weldingelectrodes 502, 504 including independent fluid shutoff for individualfluid path segments 512 a-b of a fluid path 512 according to someembodiments. Isolating electrode 502 with independent shutoff valves520, 522 may eliminate the problem of a severed loop with both endsvented to atmosphere when electrode 502 is at least partially detached.Instead, individual path segments 512 a-b (or “line segments”) may beformed, each open at only one end. In the illustrated embodiment, thevalves 520, 522 can each be a solenoid or pneumatically actuated valves,a non-return check valve, or otherwise.

It will be appreciated that the features of system 500 may be the sameor different from the corresponding features discussed herein (e.g.,welding electrodes 202, 204, shutoff valves 220, 222, welding electrodes702, 704, or the like). It will be further appreciated that althoughFIG. 5A is described here with respect to fluid path 512, the discussionherein can also apply to one or more other fluid paths, e.g., fluid path514.

In some embodiments, shutoff valves 520 and 522 may isolate segment 512a-b from the rest of the system 500 thereby shutting off fluid from thecoolant supply 508 and the coolant return 510. The shutoff valves 520and/or 522 may be controlled (e.g., electrically) or be mechanical. Theshutoff valves 520 and/or 522 may be actuated or triggered to shut offfluid flow to and/or from the segment 512 a-b when the electrode 502 isremoved and/or in anticipation of removal. In some embodiments, theremay be a limited leakage of coolant out the gap formed by full orpartial removal of the electrode 502. In some embodiments, loss ofcoolant out the gap is limited because of air pressure from theatmosphere and/or surface tension of the coolant in the segment 512 a-b.

FIG. 5B is a diagram illustrating a drawback apparatus 540 for providingindependent fluid 506 removal (or “drawback”) for each of the pathsegments 512 a-b according to some embodiments. As shown, the drawbackapparatus 540 includes four drawback elements 542-548, each positionedon a portion (or “segment”) of fluid path 512 or 514. More specifically,drawback element 542 is positioned on portion 512 a; drawback element544 is positioned on portion 512 b; drawback element 546 is positionedon portion 514 a; and drawback element 548 is positioned on portion 514b.

In the illustrated embodiment, each of the drawback elements 542-548 mayhave the same configuration and/or operation as the drawback apparatus340 discussed above. Thus, for example, each of the drawback elements542-548 may include a piston 542 a-548 a disposed within a chamber 542b-548 b. In the other embodiments, they can each have a differentconfiguration and/or operation, e.g., such as the configuration and/oroperation of drawback valve 800 or 1000, discussed herein.

FIG. 5C is a diagram illustrating a drawback fluid flow when a weldingelectrode 502 is detached, or partially detached, from the fluid flowsystem 500 according to some embodiments. Generally, for coolantpassageways (e.g., fluid path 512) of sufficiently small cross-sectionalarea, surface tension largely reduces the amount of coolant that mayescape from each isolated path (e.g., path 512 a-b), and thus the volumecapacity of the drawback apparatus 540 may be limited. For example, thetotal combined volume of four independent drawbacks elements 542-548 maybe substantially less than the previous single drawback apparatus 340.

In some embodiments, when an electrode is detached and a gap formedalong path 512, the shutoff valves 520 and 522 may engage to stop flowof coolant along the segment 512 a-b. One or both drawback elements 542and 544 may drawback fluid from the segment 512 a-b. Since the shutoffvalves 520 and 522 do not allow for coolant to be brought to segment 512a-b, the coolant may be drawn away from the gap, e.g., drawback element542 may draw coolant back from the gap along segment 512 a and drawbackelement 544 may draw coolant back from the gap along segment 512 b.

Coolant may continue to flow along path 514 even if shutoff valves 520and 522 have engaged. In one example, the coolant along path 514continues to flow to reduce temperature of the other electrode.

Although no shutoff valves are shown along path 514, it will beappreciated that there may be no shutoff valves or one or more shutoffvalves, e.g., forming a segment of path 514. FIG. 5D is an illustrationof this example.

FIG. 5D is a diagram illustrating a drawback fluid flow when bothwelding electrodes 502,504 are at least partially detached from thefluid flow system 500 according to some embodiments. By includingindependent shutoff valves 520-526 and drawback elements 542-548 foreach path segment 512 a-b and 514 a-b, both electrodes 502, 504 can bedetached at once, even simultaneously (or near simultaneously), with noor reduced coolant loss.

The drawback apparatus 540 or, more specifically, each of the drawbackelements 542-548, may drawback coolant 506 away from the gaps 533, 534formed when the welding electrodes 502, 504 at least partially detach.The arrows 550-553 indicate directions away from the gaps 533, 534 thecoolant can be drawn.

FIG. 6 is a flowchart illustrating an example operation of a fluiddrawback apparatus (e.g., drawback apparatus 540) according to someembodiments. It will be appreciated that although the steps 602-616below are described in a specific order, the steps 602-616 may also beperformed in a different order. Each of the steps 602-616 may also beperformed sequentially, or serially, and/or in parallel with one or moreof the other steps 602-616. For example, steps 602-608 can be performedsimultaneously (i.e., in parallel) with steps 610-616. In someembodiments, operation of the drawback apparatus may include a greateror lesser number of such steps.

In step 602, a first welding electrode (e.g., electrode 502) is cooledby liquid coolant (coolant 506) circulating through a first liquidcoolant path (e.g., path 512) in fluid coupling with the first weldingelectrode. In some embodiments, a coolant supply (e.g., supply 508) maysupply the liquid coolant to the first path. The liquid coolant may bewater, but as discussed above, it can be any fluid (e.g., combination ofchemicals and/or liquids). The circulating liquid coolant may cool thefirst welding electrode to a temperature to reduce or prevent a failure,e.g., melting, fusing to a work piece (e.g., work piece 110), or thelike.

In step 604, flow of the liquid coolant through the first liquid coolantpath is stopped or reduced when the first welding electrode at leastpartially detaches. For example, when the first welding electrode atleast partially detaches, e.g., in response to a failure or maintenance,the shutoff valves (e.g., valves 520, 522) may stop or reduce flow ofthe liquid coolant to and/or through the first fluid path (or portionsthereof, e.g., portion 514 a-b). As discussed above, activation of theshutoff valves may occur manually (e.g., by an operator) orautomatically (e.g., by one or more actuators, a computer, etc.).

In step 606, the liquid coolant is drawn back (e.g., by one or moredrawback apparatuses 540) in a first direction away from a gap formed inthe first liquid coolant path when the first welding electrode at leastpartially detaches. For example, a first drawback element (e.g.,drawback element 542) may draw the coolant away from the gap and intothe first element. Movement of a drawback piston (e.g., piston 542 a)may create a suction that draws coolant away from the gap and into adrawback chamber (e.g., chamber 542 b).

In step 608, liquid coolant is drawn back in a second direction awayfrom the gap formed in the first liquid coolant path when the firstwelding electrode at least partially detaches. For example, a seconddrawback element (e.g., drawback element 544) may draw the coolant awayfrom the gap and into the second drawback element. Movement of adrawback piston (e.g., piston 544 a) can create a suction that drawscoolant away from the gap and into a drawback chamber (e.g., chamber 544b). Steps 606 and 608 may occur simultaneously or nearly simultaneously.

In step 610, a second welding electrode (e.g., electrode 504) is cooledby the liquid coolant circulating through a second liquid coolant path(e.g., path 514) in fluid coupling with the second welding electrode. Insome embodiments, the coolant supply can supply the liquid coolant tothe second path. The circulating liquid coolant may cool the secondwelding electrode to a temperature to reduce or prevent a failure, e.g.,melting, fusing to a work piece (e.g., work piece 110), or the like.

In step 612, flow of the liquid coolant through the second liquidcoolant path is stopped or reduced when the second welding electrode atleast partially detaches. For example, when the second welding electrodeat least partially detaches, e.g., in response to a failure ormaintenance, the shutoff valves (e.g., valves 524,526) may stop orreduce flow of the liquid coolant. The valves 524,526 may stop or reduceflow of coolant to and/or through the second path (or portions thereof,e.g., portion 514 a-b). As discussed above, activation of the shutoffvalves may occur manually (e.g., by an operator) or automatically (e.g.,by a computer, actuator(s), etc.).

In step 614, the liquid coolant is drawn back in a first direction awayfrom a gap formed in the second liquid coolant path when the secondwelding electrode at least partially detaches. For example, a thirddrawback element (e.g., drawback element 546) may draw the coolant awayfrom the gap and into the third element. Movement of a drawback piston(e.g., piston 546 a) may create a suction that draws coolant away fromthe gap and into a drawback chamber (e.g., chamber 546 b).

In step 616, liquid coolant is drawn back in a second direction awayfrom the gap formed in the second liquid coolant path when the secondwelding electrode at least partially detaches. For example, a fourthdrawback element (e.g., drawback element 544) may draw the coolant awayfrom the gap and into the fourth element. Movement of a drawback piston(e.g., piston 548 a) may create a suction that draws coolant away fromthe gap and into a drawback chamber (e.g., chamber 548 b).

It will be appreciated that although the same liquid coolant (e.g.,coolant 506) flows through both the first and second liquid coolantpaths in the illustrated embodiment, different liquid coolant (e.g.,liquid coolant supplied from different sources and/or liquid coolant ofdifferent types) may flow through each of the first and second liquidcoolant paths in other embodiments.

FIG. 7A is a diagram of a fluid flow system 700 for cooling weldingelectrodes 702, 704 including a drawback valve apparatus 740 accordingto some embodiments. As shown, valves for each electrode can be includedwithin a drawback apparatus (e.g., drawback apparatus 540) to create thedrawback valve apparatus 740.

It will be appreciated that the features of system 700 may be the sameor different from the corresponding features discussed above (e.g.,welding electrodes 202, 204, shutoff valves 220, 222, or the like.).Accordingly, the drawback elements 742-748 may have a same or similarconfiguration and/or operation as the drawback elements 542-548described above. Likewise, the valves 720-724 may also have a same orsimilar configuration and/or operation as the valves 520-524 describedabove, although in other embodiments, the valves 720-724 may be includedwithin the drawback elements 740-746.

In FIG. 7A, coolant supply 708 provides coolant 706 along paths 712 and714 to cool welding electrodes 702 and 704, respectively. The coolant706 is then received by coolant return 710 (where the coolant 706, insome embodiments, may be recirculated). The system 700 may includeshutoff valves 720 and 722 that may shut off flow of the coolant 706along the path 712 (e.g., if a gap or a break occurs in the path 712, orpreceding the planned removal of an electrode 702). Similarly, thesystem 700 may include shutoff valves 724 and 726 that may shut off flowof the coolant 706 along the path 714. Drawback elements 742 and 744 maydraw coolant 706 into the drawback elements 742 and 744, respectively,if a gap or break forms in the path 712. Similarly, drawback elements746 and 748 may draw coolant 706 into the drawback elements 746 and 748,respectively, if there is a gap or break in the path 714.

In the example depicted in FIG. 7A, both paths 712 and 714 receivecoolant 706 from the coolant supply 708 along, at least partially, thesame path (i.e., the paths form a loop including a partially shared pathfrom the coolant supply 708). Similarly, both paths 712 and 714 providecoolant 706 to the coolant return 710 along, at least partially, thesame path.

In various embodiments, the drawback element 742 will be disposedbetween a shutoff valve (e.g., shutoff valve 720) and the electrode 702.Similarly, the drawback element 744 may be disposed between a shutoffvalve (e.g., shutoff valve 722) and the electrode 702. The drawbackelement 746 may be disposed between a shutoff valve (e.g., shutoff valve724) and the electrode 704. The drawback element 748 may be disposedbetween a shutoff valve (e.g., shutoff valve 726) and electrode 704.

In various embodiments, upon detection of a break or gap in or along thepath 712 (e.g., caused by a breach of the system and/or detachment of awelding electrode 702), the shutoff valve 720 and the shutoff valve 722may activate to block flow of coolant 706 from the coolant supply 708and block backflow of coolant 706 from the coolant return 710,respectively.

The drawback element 742 may not activate until the shutoff valve 720has shut off flow of the coolant 706. In some embodiments, the drawbackelement 742 will not activate until both the shutoff valves 720 and 722have shut off flow of the coolant 706. Once active, the drawback element742 may draw fluid away from the gap or break by pulling coolant 706into a reservoir (e.g., a chamber within the drawback element 744).

Similarly, the drawback element 744 may not activate until the shutoffvalve 722 has shut off flow of the coolant 706. In some embodiments, thedrawback element 744 will not activate until both the shutoff valves 720and 722 have shut off flow of the coolant 706. Once active, the drawbackelement 744 may draw fluid away from the gap or break by pulling coolant706 into a reservoir (e.g., a chamber within the drawback element 744).

Once the gap or break is corrected, the shutoff valves 720 and 722 maybe opened to allow flow of coolant 706. In some embodiments, thedrawback elements 742 and/or 744 may push the coolant 706 from theirrespective reservoirs back into the paths.

It will be appreciated that one or more shutoff valves may be optional.For example, the coolant supply 708 may be configured to shut itself offif a break or gap in the path of the system 700 is detected. The coolantsupply 708 may shut itself off such that little or no coolant 706 mayleak into the paths from the coolant supply 708 even if the drawbackelements 742, 744, 746, and/or 748 draw coolant 706 away from the paths(e.g., in the case of a break or gap). Similarly, the coolant return 710may shut itself off such that little or no coolant 706 may leak into thepaths from the coolant return 710 even if the drawback elements 742,744, 746, and/or 748 draw coolant 706 away from the paths.

FIG. 7B is a diagram illustrating a drawback valve apparatus 740operated by a single actuator 770 according to some embodiments. Morespecifically, the drawback valves 720-724 and drawback elements 742-748,and components thereof (e.g., piston, or the like.) are operated by theactuator 770. Although actuator 770 is shown here operating four valves722-724 and drawback elements 742-744, in other embodiments the actuator770 may operate a greater or lesser number of such valves and/ordrawback elements. The actuator 770 may be a pneumatic actuator or maybe otherwise (e.g., electric, hydraulic, mechanical, etc.). It will beappreciated that there may be any number of actuators.

In various embodiments, each shutoff valve 720, 722, 724, and/or 726 mayshare one or more actuators (or may each be associated with a separateactuator). The actuator may be coupled to any number of sensors fordetecting breaks or gaps in paths of the system 700. If a break or gapis detected, any number of actuators may control any number of shutoffvalves to shut off flow of coolant 706. Alternately, in someembodiments, the actuator(s) are mechanically controlled (e.g., througha worker).

In some embodiments, upon sensing a break, the actuator(s) may control asubset of shutoff valves. For example, if a breach in the path 712 isdetected (e.g., from detachment of the electrode 702), the actuator(s)may activate shutoff valves 720 and/or 722 to shut off coolant 706 flow.If a breach in the path 714 is detected (e.g., from detachment of theelectrode 704), the actuator(s) may activate shutoff valves 724 and 726)to shut off coolant 706 flow.

In some embodiments, the actuator(s) may control drawback elements(e.g., drawback elements 742-748). For example, after the shutoff valves720 and 722 shut off flow of coolant 706, the actuator(s) may controlthe drawback elements 742, 744, 746, and/or 748. The actuator(s) maycontrol a subset of the drawback elements. For example, after detectinga breach in the path 712, the actuator(s) may control the drawbackelements 742 and/or 744 to drawback coolant 706 from the paths (e.g.,from the breach). Upon detection or a command that the breach has beencorrected (e.g., the welding electrode 702 has been replaced), then theactuator(s) may control the drawback elements 742 and/or 744 to push thecoolant back to the paths. Similarly, after detecting a breach in thepath 714, the actuator(s) may control the drawback elements 746 and/or748 to drawback coolant 706 from the paths (e.g., from the breach). Upondetection or a command that the breach has been corrected, then theactuator(s) may control the drawback elements 746 and/or 748 to push thecoolant back to the paths.

FIG. 7C is a diagram illustrating a drawback valve apparatus 750operated by multiple actuators 770,772 according to some embodiments.Generally, more than one actuator may be employed if independent coolantcontrol is desired for each electrode 702, 704. As shown, actuator 770may control cooling for the first welding electrode 702, and actuator772 controls cooling for the second welding electrode 704. In someembodiments, the actuator 770 operates valves 720,722 and drawbackelements 742,744, and actuator 772 operates valves 724,726 and drawbackelements 746,748. Although each actuator 770,772 is shown here operatingtwo valves and drawback elements, in other embodiments they may eachoperate a greater or lesser number of such valves and/or drawbackelements. Additionally, other embodiments may include a greater numberof such actuators. In the illustrated embodiments both actuators 770,772are pneumatic actuators but in different embodiments it can beotherwise.

FIG. 8A is a diagram of a drawback valve 800 shown in a first position(e.g., an “open” position) according to some embodiments. In theillustrated example, the drawback valve 800 includes a valve element 802(e.g., a diaphragm), a spring 804, a piston 810, and a holdback pin 814,all incorporated into a drawback chamber 816 (e.g., a cylinder). Coolantmay be provided by a coolant supply 808.

As shown, the spring 804 can be pressed against, or coupled to, thevalve element 802 on one side of the spring, and pressed against, orcoupled to, an inside portion of the chamber 816 on an opposite side ofthe spring 804. Such valve element and spring arrangements can be usedin typical non-return check valves, but in this embodiment, the valveelement 802 and spring 804 are biased against the normal flow of coolantfrom supply 808 to the welding electrode (e.g., electrode 702 or 704).In operation, the valve element 802 can be forced open by a feature ofthe drawback piston 810 (i.e., holdback pin 814), allowing coolant 806to flow to the electrode through liquid coolant path 812 with chamberopening 818 serving as the coolant inlet, and chamber opening 820serving as the coolant outlet. Flow of the coolant 806 is shown bydirectional arrows 822 from inlet to outlet. In some embodiments, theholdback pin 814 may be a feature of the valve element 802, which maylikewise be forced open by the piston 810.)

Although the valve element 802 is depicted as flat, the valve element802 may be any shape to assist and/or control the flow of coolant. Forexample, the valve element 802 may be angled, concave, or any shape.Similarly, the piston 810 may be any shape.

It will be appreciated that the drawback valve 800 may be configured asa normally biased non-return valve in the outflow path of an electrodeto close upon a breach or gap at the electrode. For example, the normalflow of coolant in the opposite direction from that shown in FIG. 8A(e.g., with chamber opening 818 serving as the coolant inlet and chamberopening 820 serving as the coolant outlet) may keep the valve element inthe open position. A breach or gap in the inlet path may reduce pressureof the fluid allowing the spring and/or fluid backpressure to push thevalve element 802 into the closed position in conjunction with actuationof the piston for drawback of coolant.

FIG. 8B is a diagram of the drawback valve 800 shown in a secondposition (e.g., a “closed” position) according to some embodiments. Whenactuated, e.g., by actuator 770 or 772, the initial movement of thepiston 810 releases the valve element 802, allowing the spring 804 forceand supply 808 pressure to force it closed, thus stopping or reducingthe flow of coolant 806 to the electrode. In some embodiments, thedrawback valve 800 may mechanically close from the open position (e.g.,by coolant pressure, electrical control, or mechanical control).

FIG. 8C is a diagram of the drawback valve 800 shown in a third position(e.g., a “drawback” position) according to some embodiments. Theremaining stroke of the piston 810 draws coolant 806 back from theelectrode through opening 820 and into the chamber 816 with coolant flowthrough opening 818 blocked by the closure of valve element 802. Forexample, in some embodiments, the piston 810 may draw coolant 806 fromopening 820 serving as the coolant outlet of the valve 800 (e.g., asindicated by directional arrows 824), with the valve element 802 closedto block the supply of coolant from opening 818. In some embodiments,the direction of flow may be reversed and the piston 810 may drawcoolant 806 from opening 820 serving as the coolant inlet of the valve800, with the valve element 802 acting as a normally biased non-returncheck valve that is closed by spring and/or fluid backpressure to blockthe backflow of coolant from opening 818.

FIG. 8D is a diagram of a drawback valve 800 having a differentconfiguration. In some embodiments, instead of, or in addition to, thediaphragm 802, the drawback valve 800 may include a drawback valveelement 802 a. For example, as shown, the drawback valve element 802 amay comprise a needle-shaped drawback valve element. It will beappreciated that other types and configurations of the drawbackapparatus 800 may be implemented with the methods described herein.

It will be appreciated that the diagram of the drawback valve 800, asshown in FIGS. 8A-D, is shown in an example position relative to thewelding electrode. More specifically, the valve 800 is depicted in a“left” (or, upstream) position relative to the welding electrode. Forexample, drawback element 742 is shown in a left position relative tothe electrode 702. Accordingly, as described above, liquid coolant 806is drawn back into the drawback valve 800 through opening 820. In someembodiments, the valve 800 may also be placed in different positionsrelative to the electrode, e.g., in a “right” (or, downstream) positionrelative to the welding electrode. For example, drawback element 744 isshown in a right position relative to the electrode 702. In such aconfiguration, the valve 800 would be flipped in order to have theopening 820 on the left side of the diagram of the valve 800 (i.e., asopposed to the right side, as currently shown) in order to draw backliquid coolant 806 from the electrode through that opening 820.

FIG. 9 is a flowchart illustrating an operation of a drawback valve(e.g., valve 800) according to some embodiments. It will be appreciatedthat although the steps 902-916 below are described in a specific order,the steps 902-916 may also be performed in a different order. Each ofthe steps 902-916 may also be performed sequentially, or serially,and/or in parallel with one or more of the other steps. In someembodiments, operation of the drawback apparatus may include a greateror lesser number of such steps.

In step 902, liquid coolant (e.g., coolant 806) flowing through a liquidcoolant path (e.g., path 812) for cooling a welding electrode (e.g.,electrode 702) is received in a drawback chamber (e.g., chamber 816).For example, the liquid coolant is received in the chamber one or morechamber openings (e.g., chamber opening 818).

In step 904, the coolant is permitted to flow through the liquid coolantpath when a valve element (e.g., valve element 802), disposed within thedrawback chamber, is in an open position, thereby cooling the weldingelectrode. For example, the valve element can be in the open positionwhen the valve element is forced open by a feature of a drawback piston(e.g., piston 814), namely, a holdback pin (e.g., holdback pin 814). Insome embodiments, the valve element may be pushed open because the forcegenerated by the piston is greater than the force generated by anopposing spring (e.g., spring 804) and/or fluid pressure.

In step 906, flow of the liquid coolant through the liquid coolant pathis reduced or stopped when the valve element is in a closed position.The valve element can move to the closed position in response to asignal from an actuator (e.g., actuator 770) when the welding electrodeat least partially detaches.

In step 908, liquid coolant is drawn back away from a gap in the liquidcoolant path that is formed when the welding electrode at leastpartially detaches. For example, movement of the drawback piston cancreate a suction that draws coolant away from the gap and into thechamber, and stored at least temporarily therein (step 910).

Although operation of a single drawback valve is described here, it willappreciated that embodiments of the present invention can includeoperation of multiple such valves, operating in parallel with each otheror sequentially.

FIG. 10A is a diagram of a drawback valve 1000 in a first position(e.g., an “open” position) according to some embodiments. In theillustrated example, the drawback valve 1000 includes a valve element1002 (e.g., a diaphragm), a spring 1004, and a piston 1016 that maytravel through a piston chamber 1028.

As shown, the spring 1004 can be pressed against, or coupled to, thevalve element 1002 on one side of the spring, and pressed against, orcoupled to, an inside portion of the drawback valve 1000 on an oppositeside of the spring 1004. In some embodiments, this valve element andspring arrangements may be used as in typical non-return check valves.In some embodiments, the valve element 1002 and spring 1004 are biasedagainst the normal flow of coolant from a coolant supply (e.g., supply708) to the welding electrode (e.g., electrode 702 or 704).

In operation, the valve element 1002 may be forced open by the piston1016. In some embodiments, the piston 1016 may push on a valve elementactuator member 1018 coupled to the valve element 1002, thereby allowingcoolant (e.g., coolant 706) to flow to the electrode through liquidcoolant paths 1012, 1014 and drawback valve openings 1020, 1022, e.g.,as indicated by directional arrows 1024. In various embodiments, thepiston 1016 may push directly on the valve element 1002 to allow coolantflow through the paths 1012, 1014 and openings 1020, 1022. In someembodiments, coolant may also flow in the opposite direction with thevalve element acting as a normally biased non-return check valve.

In some embodiments, movement of the piston 1016 (e.g., as indicated bydirectional arrows 1026) may be effected by one or more actuators (e.g.,actuator 770) controlling a piston support member 1028 (e.g., pistonrod, piston shaft, etc.) coupled to the piston 1016. In otherembodiments, one or more actuators may directly control the piston 1016itself, i.e., without a piston support member 1028, e.g. directhydraulic or pneumatic actuation of the piston, electromagnetic controlof the piston, etc.

Although the valve element 1002 is depicted as flat, the valve element1002 may be any shape to assist and/or control the flow of coolant. Forexample, the valve element 1002 may be angled, concave, or any shape.Similarly, the piston 1016 may be any shape.

FIG. 10B is a diagram of a drawback valve 1000 in a second position(e.g., a “closed” and/or “drawback” position) according to someembodiments. When actuated, e.g., by actuator 770 or 772, initialmovement of the piston 1016 releases the valve element 802, and thespring 804 and/or fluid pressure pushes it closed, thus stopping orreducing the flow of coolant to the electrode. For example, the actuatorcould automatically trigger in response to a break or gap detected byone or more sensors, e.g., in the event of a failure. Alternatively, theactuator may be manually or mechanically controlled, e.g., by anoperator in order to perform scheduled maintenance.

In some embodiments, the stroke of the piston 1016, e.g., as indicatedby arrows 1018, may also draw coolant back from the electrode, or gap inthe event of a breach, through opening 1022 and into a reservoir 1030,e.g., as indicated by directional arrows 1032. For example, thereservoir 1024 can have a liquid volume capacity sufficient to evacuateall of the coolant from the passageways(s), or a capacity sufficient toensure evacuation of only the electrode. In some embodiments, liquidfrom the reservoir 1030 may be pushed back into the passageways bymovement of the piston 1016, e.g., once the breach has been repaired orscheduled maintenance completed.

It will be appreciated that the drawback valve 1000 may be configured asa normally biased non-return valve in the outflow path of an electrodeto close upon a breach or gap at the electrode. In this case, forexample, the flow of coolant may keep the valve element in the openposition. A breach or gap in the path may reduce pressure of the fluidallowing the spring and/or fluid backpressure to push the valve element1002 into the closed position in conjunction with actuation of thepiston for drawback of coolant.

FIG. 11 is a diagram of a fluid flow system 1100 for cooling weldingelectrodes 1102, 1104 including independent fluid shutoff and drawbackfor preventing or reducing liquid loss, e.g., during system 1100maintenance.

It will be appreciated that some of the features of system 1100 may bethe same or different from the corresponding features discussed above(e.g., welding electrodes 202, 204, shutoff valves 220, 222, or thelike). Accordingly, drawback apparatus (or “drawback master”) 1140 mayhave the same or similar configuration as drawback apparatus 340, and/orthe valves 1120-1128 may have a same or similar configuration and/oroperation as the valves 520-524 described above, although in otherembodiments, the valves 1120-1128 may be included within respectivedrawback apparatus 1140 and/or drawback elements (or “drawback slaves”)1142-1148.

In FIG. 11, a coolant supply 1108 provides liquid coolant 1106 to paths1112 and 1114, via supply path 1150, to cool welding electrodes 1102 and1104, respectively. The coolant 1106 may then be received by a coolantreturn 1110 (where the coolant 1106, in some embodiments, may berecirculated) via a return path 1152. The system 1100 may include a“master” valve 1120 that may shut off flow of the coolant 1106 to thepaths 1112, 1114 (e.g., if a gap or a break occurs in the path 1112and/or 1114, or preceding the scheduled removal of an electrode 1102and/or 1104). Similarly, some embodiments may include shutoff valves1122 and 1124 that may shut off flow of the coolant 1106 along the path1112 (e.g., if a gap or a break occurs in the path 1112, or precedingthe planned removal of an electrode 1102). In some embodiments, thesystem 1100 may also include shutoff valves 1126 and 1128 that may shutoff flow of the coolant 1106 along the path 1114. The drawback elements1142 and 1144 may draw coolant 1106 into the drawback elements 1142 and1144, respectively, if a gap or break forms in the path 1112. Similarly,the drawback elements 1146 and 1148 may draw coolant 1106 into thedrawback elements 1146 and 1148, respectively, if there is a gap orbreak in the path 1114.

In some embodiments, shutoff valves 1122 and 1124 may isolate fluid pathsegments 1112 a-b from the rest of the system 1100. The shutoff valves1122 and/or 1124 may be controlled (e.g., electrically) or bemechanical. The shutoff valves 1122 and/or 1124 may be actuated ortriggered to shut off fluid flow to and/or from the segment 1112 a-bwhen the electrode 1102 is removed and/or in anticipation of electrode1102 removal (e.g., for scheduled system 100 maintenance).

Similarly, in some embodiments, shutoff valves 1126 and 1128 may isolatefluid path segments 1114 a-b from the rest of the system 1100. Theshutoff valves 1126 and/or 1128 may be controlled (e.g., electrically)or be mechanical. The shutoff valves 1126 and/or 1128 may be actuated ortriggered to shut off fluid flow to and/or from the segment 1114 a-bwhen the electrode 1104 is removed and/or in anticipation of electrode1102 removal (e.g., for scheduled system 100 maintenance).

In various embodiments, the drawback element 1142 may be disposedbetween a shutoff valve (e.g., shutoff valve 1122) and the electrode1102. Similarly, the drawback element 1144 may be disposed between ashutoff valve (e.g., shutoff valve 1124) and the electrode 1102. Thedrawback element 1146 may be disposed between a shutoff valve (e.g.,shutoff valve 1126) and the electrode 1104. The drawback element 1148may be disposed between a shutoff valve (e.g., shutoff valve 1128) andelectrode 1104.

In some embodiments, the drawback elements 1142-1148 may each comprise asuction force storage element (e.g., a spring-loaded bellows). Forexample, the drawback elements 1142-1148 may include a spring 1142a-1148 a disposed within a chamber (or “housing”), and each drawbackelement 1142-1148 may be biased to draw coolant 1106 from a respectivefluid path segment. For example, the drawback element 1142 may be biasedto draw back liquid coolant 1106 from fluid path segment 1112 a; thedrawback element 1144 may be biased to draw back liquid coolant 1106from fluid path segment 1112 b; the drawback element 1146 may be biasedto draw back liquid coolant 1106 from fluid path segment 1114 a; and thedrawback element 1148 may be biased to draw back liquid coolant 1106from fluid path segment 1114 b.

In some embodiments, the drawback apparatus 1140, which may be biased toempty liquid coolant 1106 from within the apparatus 1140 to the supplypath 1150, may generate a suction force (e.g., by movement of a piston)which may be transferred to the drawback elements 1142-1148, e.g., viathe liquid coolant 1106, thereby compressing the springs 1142 a-1148 a.Upon electrode 1102 and/or 1104 removal, the springs 1142 a-1148 a mayexpand, thereby generating a suction which may draw the liquid coolant1106 away from a gap formed in the path 1112 and/or a gap formed in thepath 1114, and into the chamber of the respective drawback elements1142-1148.

Since the drawback elements 1142-1148 may be lighter and smaller thanthe drawback apparatus' described above (e.g., FIGS. 5 and 7), such aconfiguration may reduce an overall size and/or weight of the systemelements that may be located directly on the welding apparatus relativeto those described above (e.g., system 500 or system 700). Also, themaster cylinder 1140 and associated system actuating element may beremotely located from the welding apparatus to further reduce sizeand/or weight on the welding apparatus

In various embodiments, such as preceding a scheduled maintenance of thesystem 1100, the shutoff valve 1120 and the shutoff valves 1124 and 1128may activate to block flow of coolant 1106 from the coolant supply 1108and block flow and/or backflow of coolant 1106 to and/or from thecoolant return 1110, respectively.

In some embodiments, the drawback apparatus 1140 and/or drawbackelements 1142-1148 may not activate until the shutoff valve 1120, 1124and 1128 have shut off flow of the coolant 1106. In some embodiments,the shutoff valves 1122 and 1126 may be closed after drawback elements1142-1148 have been activated. Once active, the drawback elements1142-1148 may draw fluid away from a gap or break in the liquid coolantpaths 1112, 1114 by pulling coolant 1106 into a reservoir (e.g., achamber within the drawback elements 1142-1148).

Once the gap or break is corrected, e.g., upon completion ofmaintenance, one or more of the shutoff valves 1120-1128 may be openedto allow flow of coolant 1106. In some embodiments, the drawbackelements 1142-1148 may push the coolant 1106 from their respectivereservoirs back into the paths 1112 and/or 1114.

It will be appreciated that although five valves 1120-1128, one drawbackapparatus 1140, and four drawback elements 1142-1148 are shown here,other embodiments may include a greater or lesser number of suchcomponents. For example, fewer valves and/or draw back elements may beused if only one electrode is removed per maintenance cycle (i.e., onlyone electrode is detached at a given time). By way of a further example,using a master drawback apparatus for each liquid coolant path may allowthe system 1100 to function without the master valve 1120.

It will further be appreciated that one or more actuators (e.g., asdescribed herein) may be used to control operation of the drawbackapparatus 1140, drawback elements 1142-1148, and/or valves 1120-1128.For example, as described above, one or more actuators may triggeroperation of such components in preparation for a scheduled maintenanceof the system 1100. In some embodiments, such one or more actuators maybe remote actuators (e.g., located off of the welding apparatus).

FIG. 12 is a flowchart illustrating an operation of a liquid coolingsystem (e.g., system 1100) according to some embodiments. It will beappreciated that although the steps 1202-1218 below are described in aspecific order, the steps 1202-1218, in some embodiments, may also beperformed in a different order. Each of the steps 1202-1218, in someembodiments, may also be performed sequentially, or serially, and/or inparallel with one or more of the other steps. In some embodiments,operation of the liquid cooling system may include a greater or lessernumber of such steps.

In step 1202, a supply valve (e.g., supply valve 1120) is opened in asupply path (e.g., supply path 1150) to allow a liquid coolant (e.g.,liquid coolant 1106) to flow through the supply path to a firstelectrode coolant path (e.g., electrode coolant path 1112) to cool afirst welding electrode (e.g., electrode 1102) and to a second electrodecoolant path (e.g., electrode coolant path 1114) to cool a secondwelding electrode (e.g., electrode 1104). In some embodiments, the firstelectrode coolant path has a first supply-side electrode coolant segment(e.g., segment 1112 a) between the supply path and the first weldingelectrode, and a first return-side electrode coolant segment (e.g.,segment 1112 b) between the first welding electrode and a return path(e.g., return path 1152). Similarly, the second electrode coolant pathmay have a second supply-side electrode coolant segment (e.g., segment1114 a) between the supply path and the second welding electrode, and asecond return-side electrode coolant segment (e.g., segment 1114 b)between the second welding electrode and the return path. A drawbackmaster (e.g., drawback apparatus 1140) may be coupled to the supply pathbetween the supply valve and the first electrode coolant path, thedrawback master being biased to empty the liquid coolant from thedrawback master into the supply path.

In step 1204, a first valve (e.g., valve 1122) coupled in the firstsupply-side electrode coolant segment may be opened to allow the liquidcoolant to flow from the supply path through the first supply-sideelectrode coolant segment to the first welding electrode. In someembodiments, the first supply-side electrode coolant segment may have afirst drawback slave (e.g., drawback element 1142) between the firstvalve and the first welding electrode. The first drawback slave may bebiased to draw the liquid coolant from the first supply-side electrodecoolant segment.

In step 1206, a second valve (e.g., valve 1124) coupled in the firstreturn-side electrode coolant segment may be opened to allow the liquidcoolant to flow from the first welding electrode through the firstreturn-side liquid coolant segment to the return path. In someembodiments, the first return-side liquid coolant segment may have asecond drawback slave (e.g., drawback element 1144) between the firstwelding electrode and the second valve. The second drawback slave may bebiased to draw the liquid coolant from the first return-side liquidcoolant segment.

In step 1208, a third valve (e.g., valve 1126) coupled in the secondsupply-side liquid coolant segment may be opened to allow the liquidcoolant to flow from the supply path through the second supply-sideliquid coolant segment to the second welding electrode. In step 1210, afourth valve (e.g., valve 11216) may be coupled in the secondsupply-side liquid coolant segment to allow the liquid coolant to flowfrom the second welding electrode to the return path.

In step 1212, the supply valve may be closed in order to stop or reducethe flow of the liquid coolant through the supply path. Similarly, thesecond valve may also be closed to stop or reduce the flow or backflowof the liquid coolant through the first return-side liquid coolantsegment, and the fourth valve may be closed to stop or reduce the flowor backflow of the liquid coolant through the second return-side liquidcoolant segment.

In step 1214, after the supply valve, second valve and fourth valve havebeen closed, the drawback master may exert a suction force sufficient todrawback the liquid coolant from the supply path, thereby transferringthe suction force to each of the first drawback slave and the seconddrawback slave. For example, movement of a piston disposed within themaster drawback may exert the suction force. Movement of the piston maybe triggered, for example, immediately prior to the planned removal ofthe first electrode. In some embodiments, the transferred suction forcecauses the first drawback slave to discharge the liquid coolant thereininto first supply-side liquid coolant segment, and the second drawbackslave to discharge the liquid coolant therein into the first return-sideliquid coolant segment.

In step 1216, after the drawback master has exerted the suction force,the first valve may be closed in order to stop or reduce flow of liquidcoolant through the first supply-side liquid coolant segment. In someembodiments, a portion of the first supply-side liquid coolant segmentbetween the first valve and the first welding electrode, and a portionof the first return-side liquid coolant segment between the firstwelding electrode and the second valve may be isolated from the supplypath and the return path.

In step 1220, after the first valve has been closed, the first weldingelectrode may be at least partially detached, thereby causing the firstdrawback slave and the second drawback slave to exert the suction forcetransferred from the drawback master to draw the liquid coolant awayfrom a gap formed when the first welding electrode is at least partiallydetached. For example, at least partially detaching the electrode maycause springs (e.g., spring 1142 a, 1144 a), compressed by the suctionforce exerted by the drawback master, disposed within the drawbackelements to expand, thereby drawing the liquid coolant away from thegap.

FIG. 13 is a diagram of a fluid flow system 1300 for cooling weldingelectrodes 1302, 1304 including independent fluid shutoff and drawbackfor individual fluid path segments 1312 a-d of a single fluid path 1312according to some embodiments. In the illustrated embodiment, the valves1320-1326 can each be a solenoid or pneumatically actuated valves, ano-return check valve, or otherwise. In some embodiments, coolant 1306is provided to fluid path 1312 via coolant supply 1308, and coolant 1306is returned from path 1312 via coolant return 1308. In some embodiments,coolant 1306 is provided to the path 1312 from the coolant supply 1308via a supply line, and that the coolant 1306 may be returned to thecoolant return 1308 via a return line.

It will be appreciated that the features of system 1300 may be the sameor different from the corresponding features discussed herein (e.g.,welding electrodes 202, 204, shutoff valves 220, 222, welding electrodes702, 704, or the like).

In some embodiments, shutoff valves 1320-1326 may isolate segments 1312a-d from the rest of the system 1300 thereby shutting off fluid flowthrough the path 1312. The shutoff valves 1320-1326 may be controlled(e.g., electrically) or be mechanical. The shutoff valves 1320-1326 maybe actuated or triggered to shut off fluid flow to and/or from thesegments 1312 a-d when the electrodes 1302, 1304 are removed or at leastpartially detached (e.g., for a scheduled maintenance or in response toa failure).

As mentioned above, system 1300 provides, in some embodiments,independent fluid 1306 removal (or “drawback”) for each of the pathsegments 1312 a-d. As shown, the drawback apparatus' 1340-1346 may eachbe positioned on a segment of the fluid path 1312. More specifically,drawback apparatus 1340 is positioned on segment 1312 a; drawbackapparatus 1342 is positioned on segment 1312 b; drawback apparatus 1344is positioned on portion 1312 c; and drawback apparatus 1346 ispositioned on portion 1312 d.

In the illustrated embodiment, each of the drawback apparatus' 1340-1346may have the same configuration and/or operation as the drawbackapparatus 340 discussed above. Thus, for example, each of the drawbackapparatus' 1340-1346 may include a piston disposed within a chamber. Inother embodiments, they can each have a different configuration and/oroperation, e.g., such as the configuration and/or operation of drawbackvalve 800 or 1000, discussed herein.

In some embodiments, when one or both electrodes are detached and gapsare formed along path 1312, the shutoff valves 1320-1326 may engage tostop flow of coolant along the segments 1312 a-d. One or more of thedrawback apparatus' 1340-1346 may drawback fluid from the segments 1312a-d. Since the shutoff valves 1320-1326 do not allow for coolant to bebrought to segments 1312 a-d, the coolant may be drawn away from thegaps, e.g., drawback element 1340 may draw coolant back from the gapalong segment 1312 a and drawback element 1344 may draw coolant backfrom the gap along segment 1312 b, and so forth.

It will be appreciated that although four shutoff valves 1320-1326 andfour drawback apparatus' 1340-1346 are shown here, in other embodimentsa greater or lesser number of such valves and/or drawback apparatus' maybe used. Similarly, such valves and drawback apparatus may positionedelsewhere on the fluid path.

FIG. 14A is a diagram of a fluid flow system 1400 for cooling weldingelectrodes 1402, 1404 including a drawback valve apparatus 1440 and aflow sensor 1460 according to some embodiments. It will be appreciatedthat some of the features of system 1400 may be the same or differentfrom the corresponding features discussed above (e.g., weldingelectrodes 202, 204, drawback elements 742-748, or the like.).Accordingly, the drawback elements 1442-1448 may have a same or similarconfiguration and/or operation as the drawback elements 742-748described above. Likewise, the valves 1420-1424 may also have a same orsimilar configuration and/or operation as the valves 720-724 describedabove, although in other embodiments, the valves 1420-1424 may beincluded within the drawback elements 1442-1448 (e.g., as described indrawback valve 800).

In FIG. 14A, coolant supply 1408 provides coolant 1406 along paths 1412and 1414 to cool welding electrodes 1402 and 1404, respectively. Thecoolant 1406 may then be received by coolant return 1410 (where thecoolant 1406, in some embodiments, may be recirculated). The system 1400may include valves 1420 and 1422 that may adjust flow of the coolant1406 along the path 1412 (e.g., if a gap or a break is detected in thepath 1412, or preceding the planned removal of an electrode 1402).Similarly, the system 1400 may include valves 1424 and 1426 that mayadjust flow of the coolant 1406 along the path 1414. Drawback elements1442 and 1444 may draw coolant 1406 into the drawback elements 1442 and1444, respectively, e.g., if a gap or break is detected in the path 712,or preceding a scheduled maintenance. Similarly, drawback elements 746and 748 may draw coolant 1406 into the drawback elements 1446 and 1448,respectively, if there is a gap or break is detected in the path 714, orpreceding a scheduled maintenance.

In the example depicted in FIG. 14A, both paths 1412 and 1414 receivecoolant 1406 from the coolant supply 1408 along, at least partially, thesame path (i.e., supply path 1450). Similarly, both paths 1412 and 1414provide coolant 1406 to the coolant return 1410 along, at leastpartially, the same path (i.e., return path 1452).

In various embodiments, the drawback element 1442 may be disposedbetween a valve (e.g., valve 1420) and the electrode 1402. Similarly,the drawback element 1444 may be disposed between a valve (e.g., valve1422) and the electrode 1402. The drawback element 1446 may be disposedbetween a valve (e.g., valve 1424) and the electrode 1404. The drawbackelement 1448 may be disposed between a valve (e.g., valve 1426) andelectrode 1404.

In some embodiments, the valves 1420-1424 and drawback elements1442-1448, and components thereof (e.g., piston, or the like) may beoperated, or controlled, by a flow controller (or, “flow processor”)1470. Although the flow controller 1470 is shown here operating fourvalves 1422-1424 and drawback elements 1442-1444, in other embodimentsthe flow controller 1470 may operate a greater or lesser number of suchvalves and/or drawback elements. It will be appreciated that there maybe any number of flow controllers and/or actuators. In some embodiments,the flow controller 1470 may be remote from the system 1400.

In the illustrated embodiment, the system 1400 may include one or moreflow sensors 1460. As shown, the flow sensor 1460 may be positioned inthe return path 1452, although other embodiments may include one or moreother flow sensors, in addition to or instead of the flow sensor 1460.For example, other embodiments may include flow sensor(s) in the supplypath 1450, first electrode path 1412, and/or second electrode path 1414.In the illustrated embodiment, the flow sensor 1460 may detect one ormore flow rates of the liquid coolant 1406 flowing through the returnpath 1452 (e.g., 12 liters per minute). The flow sensor 1460 may detect,for example, low flow conditions in the return path 1452, which mayindicate a malfunction in the system 1400, such as an inadequate supplyof coolant, blockages in one or more of the paths, malfunctioningvalves, lost electrodes, and so forth.

In some embodiments, the flow controller 1470 may detect malfunctionsbased on the sensor data (e.g., from sensor 1460) and one or more flowconditions. For example, the flow controller 1470, or other associateddevice (e.g., a server or other processor), may compare sensor 1460 data(e.g., flow rates) to previously collected sensor data in order todetect changes in flow rate, which may indicate a malfunction.Similarly, the flow controller may compare the sensor 1460 data to athreshold value. For example, if a detected flow rate falls below apredetermined rate, then it may indicate a malfunction. Example flowconditions may include:

Inadequate Coolant Supply:

If a detected flow rate is lower than a predetermined supply thresholdrate, then it may indicate an inadequate coolant supply. Similarly, if aflow rate is reduced by at least a predetermined amount, e.g., asindicated by one or more current flow sensor measurements and one ormore previous flow sensor measurements, then it may indicate aninadequate coolant supply.

Blockage in a path (e.g., electrode path, supply path, return path, andso forth): If a detected flow rate is lower than a predeterminedblockage threshold rate, then it may indicate that one or more of pathsare blocked (or, “clogged”). Similarly, if a flow rate is reduced by atleast a predetermined amount, e.g., as indicated by one or more currentflow sensor measurements and one or more previous flow sensormeasurements, then it may indicate that one or more of paths areblocked.

Valve and Drawback Element Malfunction:

If a detected flow rate is lower than a predetermined valve thresholdrate, then it may indicate one or more malfunctioning valves and/ordrawback elements. Similarly, if a flow rate is reduced by at least apredetermined amount, e.g., as indicated by one or more current flowsensor measurements and one or more previous flow sensor measurements,then it may indicate one or more malfunctioning valves.

Lost Electrode:

If a detected flow rate is lower than a predetermined electrodethreshold rate, then it may indicate that one or more welding electrodeshave at least partially detached. Similarly, if a flow rate is reducedby at least a predetermined amount, e.g., as indicated by one or morecurrent flow sensor measurements and one or more previous flow sensormeasurements, then it may indicate that one or more welding electrodeshave at least partially detached.

In some embodiments, the flow controller 1470 may trigger one or moreaction responses based on the sensor data (e.g., detected by sensor1460) and one or more flow conditions. Example action response mayinclude:

Stop Coolant Flow:

Close one or more valves to stop coolant flow through one or more of thepaths. For example, the coolant flow may be stopped, or substantiallystopped, in the event of a lost electrode.

Drawback Liquid Coolant:

drawback liquid coolant from one or more of the paths with one or moreassociated drawback elements.

It will be appreciated that although a flow controller may detectmalfunctions, in other embodiments another device may perform suchfunctionality (e.g., a server or other processor) in addition to, orinstead of, the flow controller 1470. In various embodiments, each valve1420, 1422, 1424, and/or 1426 may share one or more flow controllers (ormay each be associated with a separate flow controller). The flowcontroller 1470 may be coupled to any number of sensors (e.g., flowsensors, temperature sensors, discussed below, and so forth), e.g., fordetecting and/or responding to malfunctions.

In some embodiments, upon detecting a malfunction, the flow controller1470 may control a subset of valves and/or drawback elements. Forexample, if a malfunction in the path 1412 is detected (e.g., based onsensor data from sensor 1460), the flow controller 1470 may activatevalves 1420 and/or 1422 to shut off coolant 1406 flow. If a malfunctionin the path 1414 is detected (e.g., based on sensor data from sensor1460), the flow controller 1470 may activate valves 1424 and 1426 toshut off coolant 1406 flow.

FIG. 14B is a diagram of the fluid flow system 1400 for cooling thewelding electrodes 1402, 1404 including the drawback valve apparatus1440, the flow sensor 1462 and flow sensor 1462 according to someembodiments.

Similar to flow sensor 1460, sensor 1462 may detect a flow rate of theliquid coolant 1406 in the supply path 1450. The sensor 1462, incombination with the sensor 1460, may provide more accurate detection ofvarious malfunctions. For example, data from sensor 1460 that mayindicate a malfunction may be confirmed by corresponding data fromsensor 1462.

In some embodiments, the flow controller 1470 may detect malfunctionsbased on sensor data from one or both of the flow sensors 1460 and 1462,and one or more flow conditions. Similar to the flow conditionsdiscussed above, example flow conditions in various embodiments mayinclude:

Inadequate Coolant Supply:

If a detected flow rate in both the supply path (e.g., by sensor 1462)and the return path (e.g., by sensor 1460) is lower than a predeterminedthreshold rate, then it may indicate an inadequate coolant supply.Similarly, if a flow rate both in the supply path and return path isreduced by at least a predetermined amount, e.g., as indicated by one ormore current flow sensor measurements (e.g., by sensors 1462 and/or1460) and one or more previous flow sensor measurements (e.g., by sensor1462 and/or 1460), then it may indicate an inadequate coolant supply.

Blockage in a path (e.g., electrode path, supply path, return path, andso forth): If a detected flow rate in both the supply path (e.g., bysensor 1462) and the return path (e.g., by sensor 1460) is lower apredetermined blockage threshold rate, then it may indicate that one ormore of paths are blocked (or, “clogged”). Similarly, if a flow rate isreduced by at least a predetermined amount, e.g., as indicated by one ormore current flow sensor measurements and one or more previous flowsensor measurements, then it may indicate that one or more of the pathsare blocked.

Valve and/or Drawback Element Malfunction:

If a detected flow rate both in the supply path (e.g., by sensor 1462)and the return path (e.g., by sensor 1460) is lower than a predeterminedvalve threshold rate, then it may indicate one or more malfunctioningvalves (e.g., valves 1420-1424) and/or drawback elements (e.g., drawbackelements 1442-1448). Similarly, if a flow rate is reduced by at least apredetermined amount, e.g., as indicated by one or more current flowsensor measurements and one or more previous flow sensor measurements,then it may indicate one or more malfunctioning valves.

Lost Electrode:

If a detected flow rate in the return path (e.g., by sensor 1460) islower than a detected flow rate in the supply path (e.g., by sensor1462) by more than a predetermined blockage threshold rate, then it mayindicate that one or more welding electrodes have at least partiallydetached. Similarly, if a difference in flow rates is increased by atleast a predetermined amount, e.g., as indicated by one or more currentflow sensor measurements and one or more previous flow sensormeasurements, then it may indicate that one or more welding electrodeshave at least partially detached.

In some embodiments, the flow controller 1470 may trigger one or moreaction responses (e.g., as described above) based on the sensor data(e.g., detected by sensor 1460) and one or more flow conditions.

FIG. 14C is a diagram of the fluid flow system 1400 for cooling thewelding electrodes 1402, 1404 including the drawback valve apparatus1440, the flow sensors 1460, 1462, and additional auxiliary equipment1454 according to some embodiments.

In some embodiments, a flow rate on a plumbing tap for auxiliaryequipment 1454 (e.g., a transformer) may be calculated based on adifference between flow rates detected by the sensors 1460 and 1462.This may be helpful, for example, to ensure that the auxiliary equipment1454, which can often be expensive, is not damaged due to improper flowwithin the system 1400.

FIG. 15 is a flowchart illustrating an example operation of a liquidcooling system (e.g., liquid cooling system 1400) configured to detectand respond to malfunctions (e.g., at least one partially detachedelectrode, clogged paths, and so forth) according to some embodiments.

It will be appreciated that although the steps 1502-1514 below aredescribed in a specific order, the steps 1502-1514 may also be performedin a different order. Each of the steps 1502-1514 may also be performedsequentially, or serially, and/or in parallel with one or more of theother steps 1502-1514. In some embodiments, detection and/or response tomalfunctions may include a greater or lesser number of such steps.

In step 1502, a first welding electrode (e.g., welding electrode 1402)is cooled by liquid coolant (e.g., coolant 1406) flowing from a supplypath (e.g., supply path 1450) through a first electrode path (e.g.,electrode path 1412) to a return path (e.g., return path 1452). Morespecifically, a coolant supply (e.g., supply 1408) may supply the liquidcoolant to the first electrode path via the supply path. Since the firstwelding electrode is included in the first electrode path, the firstelectrode is cooled by the flowing liquid coolant.

In step 1504, a second welding electrode (e.g., welding electrode 1404)is cooled by the liquid coolant flowing from the supply path through asecond electrode path (e.g., electrode path 1414) to the return path.More specifically, the coolant supply may supply the liquid coolant tothe second electrode path via the supply path. Since the second weldingelectrode is included in the second electrode path, the second electrodeis cooled by the flowing liquid coolant.

In step 1506, a supply flow rate of the liquid coolant in the supplypath may be detected by a first flow sensor (e.g., flow sensor 1462). Instep 1508, a return flow rate of the liquid coolant in the return pathmay be detected by a second flow sensor (e.g., flow sensor 1460).

In step 1510, one or more malfunctions (e.g., a clogged electrode path,one or more at least partially detached electrodes, and so forth) may bedetermined based on the detected return flow rate and the detectedsupply rate. For example, the flow controller may compare the detectedreturn flow rate and the detected supply flow rate, and if the detectedreturn flow rate is less than the detected supply flow rate, then it mayindicate a malfunction. Other flow conditions, e.g., as described above,may be used to determine a malfunction in the system.

In optional step 1512, the one or malfunctions may be identified (e.g.,by flow controller) based on flow conditions, e.g., as described above.For example, if the detected return flow rate approaches zero positiveflow, or a negative flow (i.e., backflow), then the malfunction may beidentified as detached, or at least partially detached, weldingelectrodes.

In step 1514, an action response may be triggered (e.g., by the flowcontroller 1470) based on the detected supply flow rate and the detectedreturn flow rate. For example, action responses may include, asdescribed above, opening or closing valves (e.g., valves 1420-1420) tostop or reduce liquid coolant flow, drawing back liquid coolant from theelectrode paths with one or more drawback elements (e.g., drawbackelement 1442-1448), and so forth.

FIG. 16A is a diagram of a fluid flow system 1600 for cooling weldingelectrodes 1602, 1604 including a drawback valve apparatus 1640 and flowsensors 1664, 1666 according to some embodiments. It will be appreciatedthat some of the features of system 1600 may be the same or differentfrom the corresponding features discussed above (e.g., weldingelectrodes 1402, 1404, electrode paths 1412, 1414, or the like.).Accordingly, for example, the drawback elements 1642-1648 and valves1620-1626 may have a same or similar configuration and/or operation asthe drawback elements 1442-1448 and valves 1420-1426 described above.

In some embodiments, the valves 1620-1624 may comprise proportionalcontrol valves which may adjust a flow rate of the liquid coolantflowing through their respective paths. For example, the valves1620-1464 may stop or reduce the flow of liquid coolant by moving thevalve towards a closed position, and/or increase the flow of liquidcoolant by moving the valve towards an open position. It will beappreciated that, in some embodiments, the valves 1620-1624 may eachindependently move between be the closed position, the open position,and partially closed position(s) (or, partly open position(s)), e.g., inresponse to signaling from one or more flow controllers, actuators,and/or other control device(s).

In the illustrated embodiment, the electrode paths 1612, 1614 includeflow sensors 1664 and 1666, respectively. Similar to sensors 1460, 1462,described above, the sensor 1664 may detect flow rates of the liquidcoolant 1606 flowing through electrode path 1612 and the sensor 1666 maydetect flow rates of the liquid coolant 1606 flowing through theelectrode path 1614. Individual flow sensors for each electrode pathmay, for example, allow for more accurate detection and/oridentification of malfunctions, and/or provide indication of therelative position of proportional control valves (e.g., valves1620-1624) for feedback to a proportional flow controller(s) (e.g., flowcontroller 1670) to maintain a desired flow rate in each electrode path.For example, a sudden shift in flow rate on only sensor 1664 mayindicate that the welding electrode 1602 may have detached, or at leastpartially detached. Similarly, a sudden shift in flow rate on onlysensor 1666 may indicate that the welding electrode 1604 may havedetached, or at least partially detached.

In some embodiments, more specifically, flow controller 1670 may detectmalfunctions based on sensor data from one or both of the flow sensors1664 and 1666, and one or more flow conditions. Similar to the flowconditions discussed above, example flow conditions in variousembodiments may include:

Inadequate Coolant Supply:

If a detected flow rate in both electrode paths (e.g., as detected bysensors 1664, 1666) are lower than a predetermined supply thresholdrate, then it may indicate an inadequate coolant supply. Similarly, if aflow rate in both electrode paths is reduced by at least a predeterminedamount, e.g., as indicated by one or more current flow sensormeasurements and one or more previous flow sensor measurements, then itmay indicate an inadequate coolant supply.

Blockage in a path (e.g., electrode path, supply path, return path, andso forth): If a detected flow rate in an electrode path (e.g., by sensor1664 or 1666) is lower than a predetermined blockage threshold rate,then it may indicate a blockage in that path. Similarly, if a flow ratein an electrode path is reduced by at least a predetermined amount,e.g., as indicated by one or more current flow sensor measurements andone or more previous flow sensor measurements, then it may indicate ablockage in that path.

Valve and/or Drawback Element Malfunction:

If a detected flow rate in an electrode path (e.g., by sensor 1664 or1666) is lower than a predetermined valve threshold rate, then it mayindicate one or more malfunctioning valves (e.g., valves 1420-1424)and/or drawback elements (e.g., drawback elements 1442-1448) in thatpath. Similarly, if a flow rate in an electrode path is reduced by atleast a predetermined amount, e.g., as indicated by one or more currentflow sensor measurements and one or more previous flow sensormeasurements, then it may indicate one or more malfunctioning valvesand/or drawback elements in that path.

Lost Electrode:

If a detected flow rate in an electrode path (e.g., detected by sensor1664 or 1666) is lower than a predetermined electrode threshold rate,then it may indicate that the welding electrode in that path hasdetached, or at least partially detached. Similarly, if a flow rate isreduced by at least a predetermined amount, e.g., as indicated by one ormore current flow sensor measurements and one or more previous flowsensor measurements, then it may indicate that the welding electrode inthat path has detached, or at least partially detached.

In some embodiments, the flow controller 1670 may trigger one or moreaction responses based on the sensor data (e.g., detected by sensor 1666and/or 1666) and one or more flow conditions. Example action responsesmay include:

Stop Coolant Flow:

Close one or more valves to stop coolant flow through one or more of thepaths. For example, the coolant flow may be stopped, or substantiallystopped, in the event of a lost electrode, or preceding a scheduledmaintenance.

(The decision to remove an electrode for maintenance probably won't bein response to data from a single sensor on the return. In the currentstate of the art it would even be an advanced concept for systems withthe capability to measure both flow rate and temperature for individualelectrodes.)

Reduce Coolant Flow:

Adjust (e.g., partially close) one or more valves to reduce coolant flowthrough one or more of the paths.

Increase Coolant Flow:

Adjust (e.g., open or partially open) one or more valves to increasecoolant flow through one or more of the paths.

Drawback Liquid Coolant:

drawback liquid coolant from one or more of the paths with one or moreassociated drawback elements.

In some embodiments, the flow controller 1670 may control drawbackelements (e.g., drawback elements 1442-1448). For example, after thevalves 1620 and 1622 shut off flow of coolant 1606, the flow controllermay control the drawback elements 1642, 1644, 1646, and/or 1648. Theflow controller may control a subset of the drawback elements. Forexample, after detecting a malfunction in the path 1612, the flowcontroller 1670 may control the drawback elements 1642 and/or 1644 todrawback coolant 1606 from the paths. Upon detection or a command thatthe malfunction has been corrected (e.g., the welding electrode 1602 hasbeen replaced), then the flow controller 1670 may control the drawbackelements 1642 and/or 1644 to push the coolant back to the paths.Similarly, after detecting a malfunction in the path 1614, the flowcontroller may control the drawback elements 1646 and/or 1648 todrawback coolant 1606 from the paths. Upon detection or a command thatthe malfunction has been corrected, then the flow controller 1670 maycontrol the drawback elements 1446 and/or 1448 to push the coolant backto the paths.

FIG. 16B is a diagram of the fluid flow system 1600 for cooling thewelding electrodes 1602, 1604 including the drawback valve apparatus1640 and flow sensor 1662-1666 according to some embodiments.

In some embodiments, the supply path 1650 may include flow sensor 1662.The additional sensor 1662 may provide, for example, more accuratedetection and/or identification of system malfunctions. Similar tosensors 1664, 1666, the flow sensor 1662 may detect flow rates of theliquid coolant 1606 in the supply path 1650.

In some embodiments, more specifically, the flow controller 1670 maydetect and/or identify malfunctions based on sensor data from some orall of the flow sensors 1662-1666, and one or more flow conditions. Forexample, if the flow rate detected by a sensor in either electrode pathdecreases in conjunction with an increase in flow rate detected by thesensor in the supply path, then it may indicate a malfunction, e.g., thewelding electrode in that path has detached, or least partiallydetached. Other example flow conditions are described herein.

In some embodiments, the flow controller 1670 may trigger one or moreaction responses (e.g., as described above) based on the sensor dataand/or one or more flow conditions.

FIG. 17 is a diagram of a fluid flow system 1700 for cooling weldingelectrodes 1702, 1704 including a drawback valve apparatus 1740, flowsensors 1762-1766, and temperature sensors 1780-1784 according to someembodiments. It will be appreciated that some of the features of system1700 may be the same or different from the corresponding featuresdiscussed above (e.g., welding electrodes 1402, 1404, electrode paths1412, 1414, flow sensors 1462-1466, or the like.). Accordingly, forexample, the flow sensors 1762-1766, drawback elements 1742-1748 andvalves 1720-1726 may have a same or similar configuration and/oroperation as the flow sensors 1462-1466, drawback elements 1442-1448 andvalves 1420-1426 described above.

In some embodiments, the supply path 1750 may include flow sensor 1762and temperature sensor 1780. Similarly, the electrode paths 1712, 1714may include flow sensors 1764, 1766, respectively, and temperaturesensors 1782, 1784, respectively. Although three flow sensors and threetemperature sensors are shown here, it will be appreciated that this isfor illustrative purposes only, and other embodiments may have a greateror lesser number of such flow and/or temperature sensors.

In some embodiments, the temperature sensors 1780-1784 may detect atemperature of the liquid coolant 1706 flowing through their respectivepath. This may help, for example, to maintain a predeterminedtemperature of the liquid coolant 1706, e.g., an optimal differentialtemperature for coolant entering and exiting the electrodes 1702, 1704,and/or preventing damage to system 1700 components by detectiondifferential temperatures above a predetermined threshold. In variousembodiments, by combining the flow sensors 1762 1766 with thetemperature sensors 1780-1784, the flow controller 1770 may be able todetermine a thermal transfer rate based on the detected temperature(s)and flow rate(s), which may, for example, help predict system failures(e.g., an electrode failure) or optimize welding conditions, i.e.,adjusting welding electrode current and/or cycle time.

In various embodiments, the flow controller 1770 may trigger one or moreaction responses based on the measured temperature and/or flow sensordata, and one or more flow conditions. Example flow conditions mayinclude:

Thermal Transfer Rate:

If the thermal transfer rate exceeds a thermal transfer threshold value,then it may indicate either an existing malfunction in the system, or apredicted malfunction (e.g., a welding electrode failure because thewelding electrode may be operating at excessive temperatures).Similarly, if a thermal transfer rate changes (e.g., increased) by atleast a predetermined amount, e.g., as indicated by one or more currentthermal transfer rates and one or more previous thermal transfer rates,then it may indicate either an existing malfunction in the system, or apredicted malfunction.

Liquid Coolant Temperature:

If a detected temperature (e.g., an absolute temperature or adifferential temperature) of liquid coolant flowing through a pathexceeds a threshold temperature, then it may indicate an existingmalfunction, or a predicted malfunction. Similarly, if a detectedtemperature increases or decreases by at least a predetermined amount,e.g., as indicated by one or more current temperatures and one or moreprevious temperatures, then it may indicate either an existingmalfunction in the system, or a predicted malfunction.

In some embodiments, the flow controller 1770 may trigger an actionresponse based on the detected sensor data and/or flow condition(s).Example action responses may include adjusting the temperature to apredetermined threshold, e.g., by lowering a temperature at the supply1708, adjusting valves 1720-1724 to affect flow rate(s) of the liquidcoolant 1706, and so forth. Additional action responses are describedabove (e.g., drawing back liquid coolant).

FIG. 18 is a flowchart illustrating an example operation of a liquidcooling system (e.g., liquid cooling system 1700) including flow sensors(e.g., flow sensors 1762-1766) and temperature sensors (e.g.,temperature sensor 1780-1784) according to some embodiments.

It will be appreciated that although the steps 1802-1812 below aredescribed in a specific order, the steps 1802-1812 may also be performedin a different order. Each of the steps 1802-1812 may also be performedsequentially, or serially, and/or in parallel with one or more of theother steps 1802-1812. In some embodiments, a greater or lesser numberof such steps may be included.

In step 1802, a first welding electrode (e.g., welding electrode 1702)is cooled by liquid coolant (e.g., coolant 1706) flowing from a supplypath (e.g., supply path 1750) through a first electrode path (e.g.,electrode path 1712) to a return path (e.g., return path 1752). Morespecifically, a coolant supply (e.g., supply 1708) may supply the liquidcoolant to the first electrode path via the supply path. Since the firstwelding electrode is included in the first electrode path, the firstelectrode is cooled by the flowing liquid coolant.

In step 1804, a second welding electrode (e.g., welding electrode 1704)is cooled by the liquid coolant flowing from the supply path through asecond electrode path (e.g., electrode path 1714) to the return path.More specifically, the coolant supply may supply the liquid coolant tothe second electrode path via the supply path. Since the second weldingelectrode is included in the second electrode path, the second electrodeis cooled by the flowing liquid coolant.

In step 1806, a first flow rate of the liquid coolant in the supply pathmay be detected by a first flow sensor (e.g., flow sensor 1762).Similarly, a second flow rate of the liquid coolant in the firstelectrode path may be detected by a second flow sensor (e.g., flowsensor 1764), and a third flow rate of the liquid coolant in the secondelectrode path may be detected by a third flow sensor (e.g., flow sensor1766).

In step 1808, a first temperature of the liquid coolant in the supplypath may be detected by a first temperature sensor (e.g., flow sensor1780). Similarly, a second temperature of the liquid coolant in thefirst electrode path may be detected by a second temperature sensor(e.g., temperature 1782), and a third temperature of the liquid coolantin the second electrode path may be detected by a third temperaturesensor (e.g., temperature sensor 1784).

In step 810, one or more potential malfunctions may be determined (e.g.,by flow controller 1770) based on some or all of the detectedtemperature and/or detected flow rates. For example, the flow controllermay calculate a thermal transfer rate based on the detected temperaturesand flow rates. The flow controller may then compare the thermaltransfer rate to a threshold transfer rate, and if it exceeds thethreshold, then the flow controller may predict a malfunction (e.g., anelectrode failure). Similarly, the flow controller may compare a currentthermal transfer rate with a previous thermal transfer rate, and if thedifference exceeds a predetermined amount, the flow controller maypredict a malfunction.

In step 1812, one or more action responses may be triggered (e.g., bythe flow controller) based on the detected sensor data and/or potentialmalfunctions. For example, the flow controller may close one or morevalves (e.g., valves 1720-1726) in order to stop flow of coolant throughthe electrode paths, and/or drawback liquid coolant from the electrodepaths (e.g., via drawback elements 1742-1748).

It will be appreciated that an example number of flow sensors andtemperature sensors are shown and described herein, and otherembodiments may include a greater or lesser number of such sensors. Forexample, one or more flow sensors and/or temperature sensors may beincluded on each of the supply path, return path, first electrode pathand/or second electrode path.

It will further be appreciated, as discussed in the embodiments above,that the electrodes discussed herein may be at least partially detachfor a variety reasons. For example, one or more electrodes may bedetached in preparation for a scheduled maintenance, or in response to afailure of one or more electrodes.

The present invention(s) are described above with reference to exampleembodiments. It will be apparent to those skilled in the art thatvarious modifications may be made and other embodiments can be usedwithout departing from the broader scope of the present invention(s).Therefore, these and other variations upon the example embodiments areintended to be covered by the present invention(s).

1. A system for controlling a flow of a liquid coolant to resistancewelding electrodes on a welding apparatus, the system comprising: one ormore liquid coolant paths configured to support a flow of a liquidcoolant to and from one or more resistance welding electrodes on awelding apparatus to cool the one or more resistance welding electrodes;one or more flow control valves disposed in the one or more liquidcoolant paths and configured to control a rate of the flow of the liquidcoolant in the one or more liquid coolant paths to or from the one ormore resistance welding electrodes; one or more coolant sensors disposedin the one or more liquid coolant paths and configured to measure afirst condition of the liquid coolant in the one or more liquid coolantpaths; and a controller configured to control the one or more flowcontrol valves based on the first condition of the liquid coolant in theone or more liquid coolant paths as measured by the one or more coolantsensors relative to a threshold condition of the liquid coolant in theone or more liquid coolant paths.
 2. The system of claim 1, wherein thecontroller is further configured to control the one or more flow controlvalves to increase, decrease or maintain the rate of the flow of theliquid coolant in the one or more liquid coolant paths.
 3. The system ofclaim 1, wherein at least one of the one or more coolant sensorsmeasures a first flow rate of the liquid coolant in at least one of theone or more liquid coolant paths, and the threshold condition of theliquid coolant is a predetermined flow rate value.
 4. The system ofclaim 1, wherein at least one of the one or more coolant sensorsmeasures a first temperature of the liquid coolant, and the thresholdcondition of the liquid coolant is a flow rate of the liquid coolant tomaintain the first temperature of the liquid coolant less than or equalto a predetermined temperature value.
 5. The system of claim 1, whereinthe one or more coolant sensors include two coolant sensors, the twocoolant sensors configured to measure respectively a first temperatureand a second temperature of the liquid coolant, and the thresholdcondition of the liquid coolant is a flow rate of the liquid coolant tomaintain a difference between the first temperature and the secondtemperature of the liquid coolant less than or equal to a predeterminedtemperature value.
 6. The system of claim 1, wherein: at least one ofthe one or more coolant sensors measures a first temperature of theliquid coolant entering at least one of the one or more liquid coolantpaths; at least one of the one or more coolant sensors measures a secondtemperature of the liquid coolant exiting the at least one of the one ormore liquid coolant paths; and the threshold condition of the liquidcoolant is a predetermined temperature value.
 7. The system of claim 6,wherein the controller is configured to control the one or more flowcontrol valves to maintain a difference between the first temperatureand the second temperature at or below the predetermined temperaturevalue.
 8. The system of claim 6, wherein the controller is configured tocontrol the one or more flow control valves to maintain at least one ofthe first temperature or the second temperature at or below thepredetermined temperature value.
 9. A method for controlling a flow of aliquid coolant to resistance welding electrodes on a welding apparatus,the method comprising: flowing a liquid coolant in one or more liquidcoolant paths to and from one or more resistance welding electrodes on awelding apparatus to cool the one or more resistance welding electrodes;controlling a rate of the flow of the liquid coolant in the one or moreliquid coolant paths to or from the one or more resistance weldingelectrodes using one or more flow control valves disposed in the one ormore liquid coolant paths; measuring a first condition of the liquidcoolant in the one or more liquid coolant paths using one or morecoolant sensors disposed in the one or more liquid coolant paths; andcontrolling by a controller the one or more flow control valves based onthe first condition of the liquid coolant in the one or more liquidcoolant paths as measured by the one or more coolant sensors relative toa threshold condition of the liquid coolant in the one or more liquidcoolant paths.
 10. The method of claim 9, further comprising controllingby the controller the one or more flow control valves by controlling theflow control valves to increase, decrease or maintain the rate of theflow of the liquid coolant in the one or more liquid coolant paths. 11.The method of claim 9, further comprising measuring by at least one ofthe one or more coolant sensors a first flow rate of the liquid coolantin at least one of the one or more liquid coolant paths, wherein thethreshold condition of the liquid coolant is a predetermined flow ratevalue.
 12. The method of claim 9, further comprising measuring by atleast one of the one or more coolant sensors a first temperature of theliquid coolant, wherein the threshold condition of the liquid coolant isa flow rate of the liquid coolant to maintain the first temperature ofthe liquid coolant less than or equal to a predetermined temperaturevalue.
 13. The method of claim 9, further comprising measuring by atleast two coolant sensors of the one or more coolant sensors a firsttemperature and a second temperature of the liquid coolant, wherein thethreshold condition of the liquid coolant is a flow rate of the liquidcoolant to maintain a difference between the first temperature and thesecond temperature of the liquid coolant less than or equal to apredetermined temperature value.
 14. The method of claim 9, furthercomprising: measuring by at least one of the one or more coolant sensorsa first temperature of the liquid coolant entering at least one of theone or more liquid coolant paths; and measuring by at least one of theone or more coolant sensors a second temperature of the liquid coolantexiting the at least one of the one or more liquid coolant paths;wherein the threshold condition of the liquid coolant is a predeterminedtemperature value.
 15. The method of claim 14, wherein the controllingincludes controlling the one or more flow control valves to maintain adifference between the first temperature and the second temperature ator below the predetermined temperature value.
 16. The method of claim14, wherein the controlling includes controlling the one or more flowcontrol valves to maintain at least one of the first temperature or thesecond temperature at or below the predetermined temperature value.